Terminal N-acetyl-beta-D-glucosaminyl residues in polysaccharides, glycoproteins and glycopeptides can act as acceptor. High activity is shown towards such residues in branched-chain polysaccharides when these are linked by beta-1,6-links to galactose residues; lower activity towards residues linked to galactose by beta-1,3-links. A component of EC 2.4.1.22 (lactose synthase).